Feeding device for pneumatic tools.



B. G. SANDERSON, H. D. PALMER & A. R. HODGES.

FEEDING DEVICE FOR PNEUMATIC TOOLS.

APPLICATION FILED JULY 6, 1912.

Patented Dec. 10, 1912.

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BURTON C. SANDERSON, HARVEY D. PALMER, AND ALLAN R. HODGES, OF TOPEKA,

KANSAS.

FEEDING DEVICE FOR PNEUMATIC TOOLS.

Specification of Letters Patent.

Patented Dec. 10, 1912.

To all whom it may concern:

Be it known that we, BURTON C. SANDER- SON, I'IARVEY D. PALMER, andALLAN R. Hone-Es, citizens of the United States, residing at Topeka, inthe county of Shawnee and State of Kansas, have invented certain new anduseful Improvements in Feeding Devices for Pneumatic Tools, of which thefollowing is a specification.

Our invention is an attachment for automatically feeding the tool to itswork. \Vhile of wide application, it is designed with special referenceto portable pneumatic tools, such, for instance, as portable air drills.Its special usefulness is found in drilling sheet metal, such as boilerplates, test holes, etc., where large numbers of holes are to bedrilled, and where high-speed drills are used. Its object is to feed thetool to the work uniformly and positively so as to keep the tool at itswork under uniform pressure at all times.

A further object is to provide for simplicity in construction of ourinvention. A further object is to provide for simple and efficientoperation, so that the workman may make great speed in the drilling andas well in moving the tool. from place to place to be drilled, inadjusting the tool with respect to the feed, and in manipulating orcontrolling the feeding device.

WVe attain these objects by providing the attachment herein described,comprising principally a cylinder, a piston and hollow stem workingtherein, a rod having screwthreaded engagement with and in the hollowstem, a hand-wheel-for the rod, the cylinder having inlet port leadingto one side of the piston, a spring for restoring the piston against themovement caused by under pressure brought in through said passage, and acontrolling valve for said passage.

It further consists of the parts, improvements, and combinationshereinafter set forth.

In the drawings accompanying and forming part of this specification, andin the description of the drawings, we have shown our invention in itspreferred form, and what we deem to be the best mode of applying theprinciples thereof; but it is to be understood that, within the scope ofthe appended claims, we contemplate changes in form, proportions, andmaterials, the transposition of parts, and the substitution ofequivalent members, without departing from the spirit of our invention.

Figure 1 is a sectional elevation of a device made in accordance withthe principles of our invention. Fig. 2 is a plan view, the controllingcock being shown in section on line 2 in Fig. 1. Fig. 3 is a section online 3 in Fig. 1. Fig. 4c is an elevation of a portable pneumatic toolwith our invention attached thereto. Fig. 5 is a sectional elevation ofa breast plate which is removably attachable to the feeding devicewhenever its use is desired. Fig. 6 is a view similar to Fig. 4, withparts broken away, showing a method of connecting the supply pipe forthe feeding device with the main supply pipe for controlling the feederby, or independently of, the throttle handle. Fig. '7 is an enlargedvertical sectional elevation of the union and check valve used in thatmethod of connecting. Fig. 8 is a plan view of the lower member of theunion with the check valve therein.

Similar reference characters indicate like I or corresponding partsthroughout the several views.

7 is a cylinder which is closed at the bottom' and provided with ascrew-threaded stem 8.

9 is a cap fitting on the upper end.

10 is a piston working in the cylinder and 11 is the piston rod or stemprojecting out through the cap.

12 is a short screw-threaded nipple extending below the piston. 13 is aleather washer, and 14 is a round nut screwed onto the nipple to holdthe washer in place; these parts being for the purpose of packing thepiston.

The stem 11 is hollow and internally threaded and takes in acorrespondingly externally threaded rod 15, which, projecting from theupper end of the stem, is provided with a hand-wheel 16, ascrew-threaded nipple 17, and a bearing point 18. The stem is groovedlongitudinally as shown at 19, and the set-screw 20 engages in thegroove to prevent the stem from turning with the rod.

21 is a compression spring surrounding the stem within the cylinder andbearing between the cap and the piston, and tending to force the pistonto the lower end of the cylinder, which is its normal position.

22 is an air supply pipe screwed into the shank or stem 8 andcommunicating with the cylinder under the piston through the passage 23.

24 is a three-way cock in the supply pipe capable in one position ofaffording direct passage therethrough for the air, and in anotherposition of closing the air supply and exhausting the air from thecylinder through the exhaust port 25.

30 (Fig. 4) is an outline of a portable pneumatic tool, such as an airdrill. 31 is the spindle for attaching the chuck. 32 is the air supplypipe for the, motor, the supply pipe having the throttle' 83 which alsoserves as a handle, 34 being another handle. These tools are usuallyprovided with a means opposite the drill for attaching a feeding device,in this case shown as an internally threaded socket 35, in which thethreaded stem or shank 8 may be screwed. The pipe 22 for the attachmentis extended about as shown in Fig. 4 adjacent to the throttle handle andconnected with the supply pipe, preferably back of the throttle, so asto be independent thereof. The threeway cock is also located adjacent tothe throttle handle so as to be conveniently 0perated.

The operation of our device is as follows: The too-l is placed inposition with the drill against the work and the bearing point 18against a brace. In drilling boiler sheets and the like, this braceusually consists of a temporary frame called an old man. To adjust themachine to the space between the work and the brace, the hand-wheel 16is turned to extend the rod 15; or, the cock may be turned to admit airthrough the supply pipe to the cylinder so as to force the piston andconnected parts upward or outward until the point bears against thebrace. With a long rod, however, it is understood that a wide range ofadjustment is possible in this respect. The cook 25 is opened to ad mitthe air through the supply pipe to the cylinder while the drill isrunning, so that the entire tool is forced to the work by reason of thecylinder being forced lengthwise of the piston and stem while the latterare held stationary against the brace. Preferably, when the tool isadjusted to the work, the air is first turned int-o the feeder to getproper pressure on the drill, and then the drill is started.

It is a point of special merit that with our feeding device, the drillis being forced into the work every instant, thus doing the work quicklyand preventing taking the temper out of the cutting edge by letting thetool run at high speed without cutting. When the hole is drilled, theair is shut 9ft from the motor and then from the feeder, which latter isshown in the drawings, and the spring returns the parts to normalpositions.

In Fig. 6 we have shown a modified form of connections with the mainsupply pipe. A T or other suitable connection is inserted between thethrottle handle and easing, as shown at 36, and this is connected withthe pipe 22 at 37, the union 38 inserted in this branch having a checkvalve 39, as shown in Figs. 7 and 8. This arrangement provides forcontrolling both the motor and the feeder by the throttle when thethree-way cook 24: is kept closed. The throttle is always provided witha relief port, by means of which the pressure in the feeder is relievedwhen the throttle is closed. So that with this arrangement. the startingand stopping of both drill. and feeder are controlled simultaneously bythe throttle only. The feeder may, however, be controlled independentlyof the motor by operating the cock 24, as the check valve will preventthe air from going to the motor.

It is to be understood that by means of the rod and hand-wheel thefeeding may be done by hand. But we prefer to use the rod and hand-wheelfor the purpose already stated, of initially adjusting the machine tothe work. The breast-piece 40 (Fig. 5), having the internallyscrew-threaded socket 41, may be attached to the nipple 17 if it bedesired to use the machine as a breast drill. It will thus be understoodthat our attachment in no way interferes with the ordinary range ofusefulness of this class of tools, being capable not only of automaticpneumatic feed, but also of hand feed and of use as a breast drill.

What we claim is:

1. In a device of the kind described, the combination of a cylinder thatis closed at one end and provided at its closed end with a shank adaptedto be attached to a fluidpressure tool and having a passage through saidclosed end, a cap for the other end of the cylinder, a piston working inthe cylinder and a hollow stem for the piston extending through the capand said stem having a longitudinal groove, a set-screw in the capengaging in said groove, a rod in said hollow stem having screw-threadedengagement therewith and having a threaded nipple and a bearing point atits outer end, a hand-wheel for turning said rod, a compres sion springwithin the cylinder and surrounding said stem and bearing between thecap and the piston, a supply pipe secured to said shank andcommunicating with the cylinder through said passage, said supply pipebeing adapted to be connected with the supply pipe of the tool, and athree-way cock in said first-named supp-1y pipe; substantially as setforth.

2. In a device of the kind described, the combination of a cylinder thatis closed at one end and provided at its closed end with a shank adaptedto be attached to a fluidpressure tool, a cap for the other end of thecylinder, a piston working in the cylinder, a hollow stem for thepiston, means for preventing rotary motion of the stem, a rod in saidhollow stem and having screw-threaded engagement therewith andprojecting from:

-"" supply pipe of a fluid-pressure tool, and a three-way cock in saidfirst-named supply me. p 3. In a device of the kind described, thecombination of a cylinder adapted to be attached at one of its ends to afluid-pressure tool, a piston in the cylinder, a hollow stem for thepiston, an adjusting rod in and having screw-threaded engagement withsaid stem, a compression sprlng within the cylinder and surrounding thestem and bearing between the piston and one end of the cylinder, asupply pipe communicating with the interior of the cylinder on the sideof the piston opposite the spring and adapted to. be connected with thesupply pipe of the tool, and a three-way cock in the first-named supplypipe.

4. In a device of the kind described, the

combination of a cylinder adapted to be attached at one of its ends to afluid-pressure tool, a piston in the cylinder, a stem for the piston, anadjusting rod having screwthreaded engagement with the stem, acompression sprin bearing between the piston and the cylin er forforcing the piston in one direction, a supply pipe communicating withthe interior of the cylinder to admit fluid under pressure to force thepiston in the opposite direction, and a three-way cock in said supplypipe.

5. In a device of the kind described, the combination of a cylinder, apiston therein, a stem for the piston projecting from the cylinder,means for admitting fluid under pressure into the cylinder to force thepiston in one direction and means for forcing the piston in the oppositedirection; said device being formed with a bearing at one end and beinformed at its other end so as to be capa le of attachment .to the casingof a pneumatic tool.

In testimony whereof we have aflixed our signatures in presence of twowitnesses.

BURTON C. SANDERSON. HARVEY D. PALMER. ALLAN R. HODGES.

Witnesses:

HENRY H. SERVICE, J. M. STARK.

